Electronic switching device



Nov. 18, 1952 5I VAN MIE-RL() 2,618,753

ELECTRONIC SWITCHING DEVICES Filed April 16, 1951 51A M5L/1 S VA N M/ERL o A TTOR/VEY Patented Nov. 18, 1952 ELECTRONIC SWITCHING DEVICE Stanislas Van Mierlo, Antwerp, Belgium, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application April 16, 1951, Serial No. .221,157 In France April 14, 1950 Claims. 1

The present invention relates to electronic switching devices and more particularly to such devices utilizing rectifying cells such as germanium diodes.

An electronic switching device using rectifying cells constitutes a device analogous to an electrical contact, that is to say, to a device the attenuation of which can have any one of the two values 0 and innity In fact electronic switching devices of the above mentioned type provide an attenuation variable according to the inherent characteristics of the rectifying cells used but never reach the values 0 or infinity. It is obviously of interest to provide switches for l which the ratio between the maximum attenuation and the minimum a-ttenuation is as great as possible.

One of the objects of the present invention is to provide an electronic switch utilizing rectifying cells such as germanium diodes in which the ratio between the maximum and the minimum attenuations is greater than in the case of switches of the type at present in use.

According to another feature of the invention an electronic switch comprises, in combination, two terminals connected respectively to ground through an impedance, a pair of rectifying cells oppositely connected between the said two terminals, a terminal connected to a common point to the said two rectifying cells by an impedance, means adapted to bring the said terminal to a positive or negative potential of suitable value, a second pair of rectifying cells oppositely connected between the said two terminals in parallel with the first pair of rectifying cells and in the same direction, associated with means adapted for carrying the point common to the second pair of recltifying cells to a suitable potential, the direction of the said rectifying cells and the value and the direction of the Said potential being chosen in order that the said switch produces on the signals transmitted between the said two terminals a high or a low attenuation according to the direction of the potential of the said terminal connected to a common point to the rst pair of rectifying cells.

Other objects, features and advantages of the present invention will appear from a reading of the following description of an embodiment utilizing features of the invention, the said descrip- `tion being given in connection wtih the accompanying drawings in which:

Fig. 1 represents a known electronic switching device utilizing rectifying cells such as germanium diodes;

Fig. 2 represents an electronic switch incorporating features of the present invention;

Fig. 3 represents an alternative of the device shown in Fig. 2.

It will be assumed that the signals, the maximum amplitude of which is V, are transmitted between terminal I and terminal 2 (Fig. l). If terminal 3 is carried to a positive potential with respect Ito ground, equal or greater than V, a current flows between terminal 3 and ground through the rectifying cells 4 and 5 and the impedances 6, "I and 8. In this case, the signals are subjected between terminals I and 2 only to a small attenuation. If terminal 3 is carried to a potential equal or greater than V in absolute value and negative with respect to ground, no current will iiow through the rectifying cells 4 and 5 and the signals are subjected between terminals I and 2 to a high attenuation. Under certain circumstances of operation, it is interesting to provide a ratio as great as possible between the maximum and minimum attenuations provided for the signals by the circuit shown in Fig. 1. On the other hand the portion of the signals passing towards terminal 3, in the case in which the attenuation is a minimum, may be reduced by giving to impedance 6, which may, for instance, be a self inductance, a suitable value.

Fig. 2 represents an electronic switch capable of transmitting electrical signals between terminals 9 and I0. If there is applied a negative voltage with respect to ground (-V) from a source Il lto terminal II and positive voltage with respect to ground (+V) from a source I2 to terminal I2, it is easy to see that no current will ow between terminal Il and ground through the rectifying cells I3 and I4 and the impedances I5,l I6 and I'I, and the cells I3 and I4 provide a high impedance for the passage of electrical signals between terminals 9 and I0. On the other hand, a current iiows between terminal I2 and ground through rectifying cells I8 and I9 and impedances I5 and I6; in view of this the signals sent either from terminal 9 or from terminal I 0 are free to pass towards terminal I2 and to ground through source I2', the rectifying cells I8 and I9 offering them a low impedance. The attenuation obtained by means of the electronic switch circuit represented by Figure l is therefore increased due to the absorption of the signals towards terminal I2 through the rectifying cells I3 and I9 which in this case offer a low impedance. If there is applied a positive potential Vi from the source II" to terminal I I which potential is positive with respect to ground (Vi f 3U Aandthus to ground. through source 3U. f terminal 2t is carried toa positive potential by connecting to the source 26'?, a current will ilow between Aterminal 24 and ground through .the impedance 29, 3|., 32, 33 and 34 andthe rectifyl ing cellsV 25, 2G, 21 and 28 which then oier a low `impedance tothe passage of the signals between terminals 22 and 23; on theother hand if the .positive potential applied to terminal 24 from i source 24" is chosen in a suitable way, points a 35, 36, 31, and 38 areat a positive potential greater being greater than V) a current ilows between terminal II and ground through the rectifying cells I3 and I4 and the impedances I5, I6 and II; points 2U and 2| are then positive with respect to ground and if the values of the impedances I5, I6 and I'I and the value of potential V1 have been `chosen in a suitable way, the potential of points 2E! and 2| is then greater than the potential V of terminal I2. In this case no current flows between terminal I2 and ground through the rectifying cells which thenpresenthav high impedance. The electrical signals transmitted between terminal 9 and terminal ID are subjected velectronic switch adapted for transmittingy electrical signals between 'terminals 22 Vand 23. If

terminal 24 is at a negative potential -V with respect to ground fromrthe source 24 and terl minal 3|! at a positive potential +V withrespect to Vground from theisource 30', a current will owbetween terminal 38 and groundthrough Yimpedances 3I, 32, 33, 34 and rectifying cells 39,

dil, Illv and 112 which offer alow impedance for the passage of signals-towardsterminal 39 and y vto ground through source 39'; on the other hand no current will flow through-the rectifying cells 25, 26,' 21 and 28, provided that the potential Hof-.terminal 3.9 and the value of the impedances 3|, 32, 33 and 34 have been chosen in such a way .that, on theorie hand,y the potential of point 35 is greater-than the potential of point 36 and that,

on .the otherhand, the potential of point 38 is greater than the potential of point 3'I.

There is, as in the vcase ofthe circuit shown in Fig.2 a high impedance which is opposed to f-thepassage of the signals either from -terminal -22 to terminal 23 or from terminal 23 to'terminal 22, `while a low shunt impedance is provided Whichvpermits shunting signals transmitted from terminal 22 or from .terminal 23 towards terminal If than-the potential of terminal 30 and no current will then now through the rectifying cells 39, 40, Myand 42lwhich then offer a high impedance .between terminals 22 and 23 and terminal 3U.

There is thus obtained between terminals 22 and 23 series rectifiers offering low impedances and shunt rectiers offering high impedances.

While the principles of the invention have been described above in connection with specic embodiments, and particular modifications thereof, it is to be clearly understood that this descriptionis'rnade only by way ofexample and not as a limitation on the scope of the invention.

What is claimed is that:

l; Switching means for controlling energy transfer between an energy source and a load l comprising, -in combination, a rst pair of asymonly to a low attenuation, and the ratio between -A f metrically'conducting devices connected in series `between saidenergy source and said load, the twofsaid asymmetrically conducting devices havingtheir like electrodes connected together, a

second ,pair of asymmetrically conducting devices connected in series between said source and said load, the two last-mentioned asymmetrically conducting devices-having their like electrodes connected rtogether, the same electrodesA beingv con- Vneet-.ed together in both pairs, a resistor connected to the junction point of said first pairyazrst voltage source connected betweentheother end l of said'resistor and ground, and` a second voltage source connected directly between the junction point of said second pair and ground. y

2. Switching meansaccording to claim 1",-fur ther comprising a second resistor connected -be- -tween said energy source and ground andathird resistor connected between said load and ground.

3.Switching-rneans, according to claim 2," fur- Y ther-comprising a third -voltage source of apredetermined value, and means to replace the iirst source with said third source.

4. Switching'means, according to-claimj3, in which the upotential of the first source is'opposite in sign-from. that of the secondsource'and'rthe potential of the thirdy source is the same sign as said second source but greater in value.

5..-Switching means, according to: claim 4, in which each asynnnetrically.conductingV device of l the rstpair includes a pair of series-connected asymmetrically conducting devices,-poled inthe f same direction, a resistance connected between vthe junction `point of each pair of said devices and ground, and further comprising a lresistance and an asymmetrically conductive device connectedbetween each said junction point-and the second voltage source, said last-mentioned-` de- Y vices being connected to said junction points 'and being poled in the same direction withfrespect tosaid second voltage source as-'the second pair of devices. Y

STANISLAS VANMIERLO.

REFERENCES. CITED "The cllowing references are of ,recordin the iile of this patent:

UNITED STATES. PATENTS 

